308 TEREBRATULID^. 



Terebratula, Mliller, 1176. 



Etym. — Diminutive of terebratus, perforated. Lamp-shell. 



Syn. — Lampas, Humph., 1791. Gryphus, Muhlfelclt, 1811, 

 Epithyris, Phil., 1841. Liothyris, Douville, 1879. 



Dislr. — 8 sp.. West Indies, Mediterranean ; 90-250 fathoms 

 on nullipore mud. (Forbes.) Vigo Bay, Falkland Islands, 

 Japan. Fossil, very numerous species. Triassic — ; world-wide. 

 T. maxillata^ Sowb. (cxxxiv, 2). T. vitrea, Linn, (cxxxiv, 6, 1). 

 T. sella, Sowb. (cxxxiv, 5). T. Phillipsii, Morris (cxxxiv, 3, 4). 



Shell smooth, convex; beak truncated and perforated; foramen 

 circular ; deltidium of two pieces frequently blended ; loop very 

 short, simple, attached by its crura to the hinge-plate. 



Animal attached by a pedicel; brachial disk ti'ilobed, centre 

 lobe elongated and spirally convoluted. 



Douvilld has proposed the name Liothyris for shells without 

 folds, like T. vitrea, L. (cxxxiv, 6, 7), but there are so many 

 intermediate stages that the division cannot be maintained; some 

 young individuals are unfolded, but acquire the folds in growth. 



pyCrOPE, Link, 1830. (Diphytes Schrot., 1779. Antinomia, 

 Catullo, 1850. Pugites, DeHaan, 1833. Glossothyris, Douville, 

 1879.) Ventral valve bilobed when young; when adult, the lobes 

 unite, leaving a round hole in the centre of the shell. Jurassic 

 and Cretaceous; Southern Europe. T. diphoides, d^Orh. (cxxxiv, 

 8-10). T. diphya, Colonna (cn-xxiv, \1\ 



DiCTYOTHYRis, Douvllle, 1879. Ventral valve two-folded with 

 a median depression; dorsal valve with a strong median swelling, 

 bordered by channels; surface radiately striate, crossed by con- 

 centric growth-lines forming tubercles at their intersection. 

 Jurassic and Cretaceous. 



ccENOTHYRis, Douville, 1879. Shell oval, smooth; tooth-plate 

 strongly developed ; apophyses independent of the cardinal teeth, 

 from which they are separated by a diverging slit ; a septum 

 present, as in Waldheimia. T. vulgaris, Schloth. (cxxxiv, 12). 



DiELASMA, King, 1859. 



Syn. — Epithyris, King (part), 1850. Seminula, M'Coy (part), 

 1855. Cyrptacanthia, White and St. John, 1868. 



Distr. — Permian — ; Eur., N, Am. D. elongafa, Schloth. 

 (cxxxiv, 13). 



Shell with lamellae supporting the teeth of the neural valve, 

 a short loop as in Terebratula but more abruptly sinuated ante- 

 riorly, and with the central lamina of the hinge-plate in the 

 haemal valve produced in the form of a mason's trowel, and 

 supported beneath b}'^ a mesial septum. 



Terebratulina, d'Orbigny, 1847. 

 Syn. — Agulhasia, King, 1871. 

 Distr. — 8 sp. United States, Norway, Australia, Cape, Japan ; 



